Question

which of the following is not always necessary to observe a shadow​

Answer 1

A shadow will not form if any of these is absent. This explains why we cannot see a shadow in the dark. It is only when light rays are obstructed by an opaque object that we get a shadow of the object.l

Answer 2

Answer:

(a) Sun is not always necessary to observe a shadow because any source of light, an opaque object and a screen are just necessary enough to see a shadow